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Undescended Testis (Cryptorchidism)

What happens under normal conditions?

Normal testicles (testes) arise early in a boy's development. Although they are located initially in the abdominal cavity, they descend or drop into the scrotal area during the latter part of pregnancy, in response to the baby's normal hormones. The testicles in the infant make sperm and the male sex hormone testosterone .The purpose of the scrotum is to allow the testis to be in a cooler environment than the body, because sperm cannot develop at body temperature. During childhood, sperm in the testicles are undergoing a maturation process that ultimately results in mature sperm at puberty. If the testicles are undescended, meaning not in the scrotum, then the sperm do not mature. The longer this lasts, the lower the chances that the sperm in the affected testicle will mature normally.

What are undescended testicles and how are they diagnosed?

In children with an undescended testicle (testis), the testicle fails to reach the normal position in the scrotum. This condition is obvious on routine examination in the infant and is present in about 3-4% of newborns (and up to 21% of premature newborns). Fortunately, about half of these testicles will descend spontaneously during the first three months of life. Testicles will not descend spontaneously after three months of age. Consequently, about 1% to 2% of boys will need treatment. It is important not to confuse undescended testicles with "retractile" testicles. After six months of age, normal babies and male children have a reflex that pulls the testicles up to protect them when he is cold or frightened. These testicles are in the scrotum at other times and do not require any treatment. An expert physical examination may be needed to distinguish these, and it is important, as only truly undescended testicles need treatment.

The testicles need to be at a temperature that is two to three degrees lower than normal body temperature to produce sperm normally. Fortunately, the scrotum is several degrees cooler than body temperature and hence is the ideal location for the testicle. Testicles that do not descend into the scrotum will not function normally. Because they may not make sperm, they can be a cause of infertility, especially when both testicles are affected. They are also associated with a higher risk of testicular cancer in adulthood (although the risk is still less than one in 100). Many times there is also an associated hernia when the testicles fail to descend normally.

What causes undescended testicles?

In most children with this condition it is not known why the testicles fail to descend. It may be because the testicles are not normal to start with. In other cases there is a mechanical problem that leads them to descend or drop but miss the scrotum, and end up adjacent to the scrotum (these are called "ectopic testicles"). Or, it may be that the infant's hormones may be insufficient to stimulate the testicles normally. It is important, however, to realize that there are no studies showing that the problem is caused by anything that the mother did or ate during pregnancy.

What if the testicle cannot be felt on physical examination?

A testicle that cannot be felt on physical examination is called "nonpalpable". Nonpalpable testicles may be located in the abdomen, absent or atrophic (very small). It is important to determine which of these is true because a testicle left inside the abdomen could form a tumor later in life. Such a tumor may go undetected until it becomes quite large or causes symptoms. Unfortunately, there is no radiologic study, such as an ultrasound, that can definitively determine whether a testicle is present, so this situation always requires surgery. Most surgeons use a technique called laparoscopy. They will find one of three situations: 1) blind ending testicular blood vessels suggesting an absent testicle; 2) vessels exiting the abdomen, proving that there is no testicle within the abdominal cavity; or 3) a testicle in the abdomen. If a testicle is found, it is brought down into the scrotum or removed, depending on its condition and location.

What treatment(s) are available?

Treatment is recommended anytime after six months of age. The time between six and 18 months of age is generally considered best, when taking into account surgical and anesthetic factors. Medical or hormonal treatment is not indicated. In addition, the testis will not descend spontaneously after 3 months of age. Consequently, the only available treatment option is surgery. This operation is called an orchiopexy. It requires general anesthesia, but the baby can almost always go home the same day and usually acts entirely normal within one to two days. An incision about an inch long is made in the groin area (usually it can hardly be seen later). The testicle is separated from all surrounding tissues (and if there is a hernia, this is fixed at the same time) so that it comes easily into the scrotum where it is stitched into place. In some cases, the testicle is too high for this simple operation and more complex procedures (and sometimes even two operations) are needed. Overall, the success rate with surgery is 98%.

What can be expected after treatment?

After treatment, the testicle usually develops to normal size in the scrotum. However, in some cases the testicle is abnormal to start with and never grows properly. In other cases, even though it is of normal size, sperm never develop. In most cases of an undescended testicle on one side, the chances of ultimately fathering a child are very high — virtually the same as normal. It is recommended that, as a teenager, these patients have regular physical examinations and be reminded to perform monthly testicular self-examination because of the slight risk of testicular cancer, which can occur even after successful surgery.

Is an undescended testicle always diagnosed in babies?

No. Increasingly, many boys are being diagnosed with an undescended testicle later in childhood, often between 6 and 10 years of age. These boys had normally descended testicles as infants. This condition is called an “ascending testicle”. The cause is uncertain. However, most think that the spermatic cord does not grow normally as the child grows, and gradually the testis becomes undescended. Often these boys are known to have a retractile testis before the diagnosis of an ascending testicle is made. These testicles need surgical treatment to move the testicle into the scrotum, because sperm maturation will not occur if the testicle remains undescended. For these reasons, it is important that boys undergo genital examination during their annual well child visits to the pediatrician or family physician.

Reviewed: January 2011

Last updated: March 2013

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Undescended Testis Glossary
  • abdomen: Also referred to as the belly. It is the part of the body that contains all of the internal structures between the chest and the pelvis.

  • abdominal: in the abdomen, the cavity of this part of the body containing the stomach, intestines and bladder.

  • anesthesia: Loss of sensation in any part of the body induced by a numbing or paralyzing agent. Often used during surgery to put a person to sleep.

  • anesthetic: A substance that causes lack of feeling or awareness.

  • cancer: An abnormal growth that can invade nearby structures and spread to other parts of the body and may be a threat to life.

  • descended: Lowered.

  • diagnosis: The process by which a doctor determines what disease or condition a patient has by studying the patient's symptoms and medical history, and analyzing any tests performed (e.g., blood tets, urine tests, brain scans, etc.).

  • ectopic: Used to describe an organ or body part occurring in a position or form that is not usual.

  • fertility: The ability to conceive and have children.

  • gene: The basic unit capable of transmitting characteristics from one generation to the next.

  • general anesthesia: Person is put to sleep with muscle relaxation and no pain sensation over the entire body.

  • groin: The area where the upper thigh meets the lower abdomen.

  • hernia: Condition in which part of an internal organ projects abnormally through the wall of the cavity that contains it.

  • hormone: A natural chemical produced in one part of the body and released into the blood to trigger or regulate particular functions of the body. Antidiuretic hormone tells the kidneys to slow down urine production.

  • incision: Surgical cut for entering the body to perform an operation.

  • infertility: The diminished ability or the inability to conceive and have offspring.

  • ions: Electrically charged atoms.

  • laparoscopy: Surgery using an instrument in the shape of a tube that is inserted through the abdominal wall to give an examining doctor a view of the internal organs.

  • orchiopexy: A surgical repair that involves moving an unlowered testicle into the sac (scrotum) that holds the testicles.

  • palpable: Able to be felt by the hands especially during medical examination.

  • pregnancy: The condition of being pregnant.

  • radiologic: X-ray.

  • scrotal: Relating to the scrotum, the sac of tissue that hangs below the penis and contains the testicles.

  • scrotal: Relating to the scrotum, the sac of tissue that hangs below the penis and contains the testicles.

  • scrotum: Also referred to as the scrotal sac. The sac of tissue that hangs below the penis and contains the testicles.

  • sperm: Also referred to as spermatozoa. Male germ cells (gametes or reproductive cells) that are produced by the testicles and that are capable of fertilizing the female partner's eggs. Cells resemble tadpoles if seen by the naked eye.

  • spermatic cord: A cord by which a testis is suspended in the scrotum.

  • testes: Also known as testicles. Paired, egg-shaped glands contained in a pouch (scrotum) below the penis. They produce sperm and the male hormone testosterone.

  • testicle: Also known as testis. Either of the paired, egg-shaped glands contained in a pouch (scrotum) below the penis. They produce sperm and the male hormone testosterone.

  • testicular: Relating to the testicle (testis).

  • testicular cancer: Cancer of the testis.

  • testis: Also known as testicle. Either of the paired, egg-shaped glands contained in a pouch (scrotum) below the penis. They produce sperm and the male hormone testosterone.

  • testosterone: Male hormone responsible for sexual desire and for regulating a number of body functions.

  • tissue: Group of cells in an organism that are similar in form and function.

  • tumor: An abnormal mass of tissue or growth of cells.

  • ultrasound: Also referred to as a sonogram. A technique that bounces painless sound waves off organs to create an image of their structure to detect abnormalities.

  • undescended testicle: Also called cryptochidism. A condition seen in newborns whereby one or both of the male testes have not passed down into the scrotal sac.

  • urge: Strong desire to urinate.

  • urology: Branch of medicine concerned with the urinary tract in males and females and with the genital tract and reproductive system of males.

Undescended Testis Anatomical Drawings

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